Another source on why dropping the bombs was necessary to end the war:
http://www.spiritus-temporis.com/at...bate-over-the-decision-to-drop-the-bombs.html
The weekly standard articel points out the intercepted military radio transmissions that pointed to the massive buildup on kyushu before the dropping of the bombs, and the above article points out why the japanese military played a decicive role in refusing to surrender:
While some members of the civilian leadership did use covert diplomatic channels to begin negotiation for peace, on their own it could not negotiate surrender or even a cease-fire. Japan, as a Constitutional Monarchy, could only enter into a peace agreement with the unanimous support of the Japanese cabinet, and this cabinet was dominated by militarists from the Japanese Imperial Army and the Japanese Imperial Navy, all of whom were initially opposed to any peace deal. A political stalemate developed between the military and civilian leaders of Japan with the military increasingly determined to fight despite the costs and odds.
****the determination of the japanese military to continue fighting before the bombs dropped:
Historian Victor Davis Hanson points to the increased Japanese resistance, futile as it was in retrospect, as the war came to its inevitable conclusion. The Battle of Okinawa showed this determination to fight on at all costs. More than 120,000 Japanese and 12,000 American troops were killed in the bloodiest battle of the Pacific theater, just 8 weeks before Japan's final surrender. When the Soviet Union declared war on Japan on August 8, 1945 and carried out Operation August Storm, the Japanese Imperial Army ordered its ill-supplied and weakened forces in Manchuria to fight to the last man, an order which it carried out. Major General Masakazu Amanu, chief of the operations section at Japanese Imperial Headquarters, stated that he was absolutely convinced his defensive preparations, begun in early 1944, could repel any Allied invasion of the home islands with minimum losses. The Japanese would not give up easily because of their strong tradition of pride and honor: Many followed the Samurai code and would fight until the very last man was dead.
****Even after Hiroshima and Nagasaki were bombed, it took intervention by the Emperor to end the war:
After the realization that the destruction of Hiroshima was from a nuclear weapon, the civilian leadership gained more and more traction in its argument that Japan had to concede defeat and accept the terms of the Potsdam Declaration. However, even after the destruction of Nagasaki, the Emperor himself needed to intervene to end a deadlock in the cabinet.
****How did the bombings help end the war from the Japanese side:
According to some Japanese historians, Japanese civilian leaders who favored surrender saw their salvation in the atomic bombing. The Japanese military was steadfastly refusing to give up, so the peace faction seized on the bombing as a new argument to force surrender. Koichi Kido, one of Emperor Hirohito's closest advisors, stated: "We of the peace party were assisted by the atomic bomb in our endeavor to end the war." Hisatsune Sakomizu, the chief Cabinet secretary in 1945, called the bombing "a golden opportunity given by heaven for Japan to end the war." According to these historians and others, the pro-peace civilian leadership was able to use the destruction of Hiroshima and Nagasaki to convince the military that no amount of courage, skill and fearless combat could help Japan against the power of atomic weapons. Akio Morita, founder of Sony and a Japanese Naval officer during the war, also concludes that it was the atomic bomb and not conventional bombings from B-29s that convinced the Japanese military to agree to peace.
****What the bombings may have stopped:
Supporters of the bombing also point out that waiting for the Japanese to surrender was not a cost-free option—as a result of the war, noncombatants were dying throughout Asia at a rate of about 200,000 per month. The firebombing had killed well over 100,000 people in Japan, since February of 1945, directly and indirectly. That intensive conventional bombing would have continued prior to an invasion. The submarine blockade and the U.S. Army Air Force's mining operation, Operation Starvation, had effectively cut off Japan's imports. A complementary operation against Japan's railways was about to begin, isolating the cities of southern Honshu from the food grown elsewhere in the Home Islands. This, combined with the delay in relief supplies from the Allies, could have resulted in a far greater death toll in Japan, due to famine and malnutrition, than actually occurred in the attacks. "Immediately after the defeat, some estimated that 10 million people were likely to starve to death," noted historian Daikichi Irokawa. Meanwhile, in addition to the Soviet attacks, offensives were scheduled for September in southern China, and Malaysia.
Supporters also point to an order given by the Japanese War Ministry on August 1, 1944. The order dealt with the disposal and execution of all Allied POWs, numbering over 100,000, if an invasion of the Japanese mainland took place. (It is also likely that, considering Japan's previous treatment of POWs, were the Allies to wait out Japan and starve it, the Japanese would have killed all Allied POWs and Chinese prisoners.)